Wide Chord Fanblades on Turbofan Engines

[disco87]

Hi,

I'm having a little trouble understanding how these can increase the thrust of a turbofan. My understand is that they utilise the fact that the tips are moving faster than the center parts. Therefore they are able to accelerate a greater mass flow of air which translates into greater thrust.

Is this because these engines are generally high bypass, where most of the thrust comes from the bypass air. This would mean that if the tips of the blades are acceleration more air, more air will be bypassed which produces more thrust?

Or is could be completely wrong in my whole understanding.

Thanks

[lomapaseo]

any blade has the tip moving much faster than the inboard, Fan blades of even narrow chord produce more air out at the tip than at their inner flow. You can get lots of thrust out of narrow chord as well.

The secret to the wide chord is that you can get a very high Hub to tip ratio flow over a wide speed range without the clap-trap drag of variable inlet guide vanes in font of the fan. The wide chords give an excellent base ( at the root attachment) to allow wierd twists of the airfoil to avoid inlet guide vanes. Try this with narrow chords and your sure to get blade flutter.